A Table showing the Illuminated Portions of the Discs of Venus and Mars. THE numbers in this table are the versed sines of that portion of the discs which, to an observer on the Earth, will appear to be illuminated, the apparent diameters of the planets at the time being considered as unity. To a spectator on the Earth, Venus appears most brilliant when her elongation is about 45°, and she is approaching her inferior conjunction, or receding from it; in which positions she will be on the 6th of April and the 18th of June. Mars is most brilliant about the time of his opposition to the Sun, being then also nearest to the Earth; in which position he will be on the 18th of December. Position and Magnitude of the Rings of Saturn, according to Bessel and Struve, for every fortieth day in the year, at 7 hours in the morning. a denotes the outer semi-transverse axis of the outer ring. outer semi-conjugate axis of the outer ring, positive when the northern surface is visible, negative when the southern. inclination of the northern semi-conjugate axes of the rings to the circle of declination; + when East, - when West. angle of elevation of the Earth above the plane of the rings, as seen from Saturn; when North, when South. "angle of elevation of the Sun above the plane of the rings, as seen from Saturn; + when North, when South. The inner semi-transverse axis of the inner ring is two thirds of a diminished by 0".07. The inner semi-conjugate axis of the inner ring is two thirds of b. The Opposition will take place on the 27th of September. LATITUDE AND LONGITUDE OF THE PRINCIPAL PLACES IN THE UNITED STATES, ETC., WITH THEIR DISTANCES FROM WASHINGTON. [The Longitudes are reckoned from Greenwich.] The Capitals (Seats of Government) of the States and Territories are designated by Italic Letters. Castine, Charlestown (Navy Yard), 4 35 Charleston (St. Mich.'s Ch.), S. C. 32 46 33 79 57 275 19 49.8 544 Mass. 42 2 23 70 34 484 42 19.2 507 Mass. 42 22 71 3 334 44 14.2 433 Chicago, Cincinnati (Fort Wash'n), Columbia, Columbus, Concord (State-House), Dayton, Dedham (1st Cong. Ch.), Detroit, Dorchester (Ast. Observ.), |